Machine Type Communication (MTC) devices (sometimes referred to as Machine to Machine (M2M) devices) are typically unmanned devices. Unmanned devices typically operate autonomously without a user controlling their normal operation. Unmanned devices are configured to establish communication with and exchange information with at least one server or a central network so that the server(s) or central network can provide a service to users of the MTC devices. MTC devices may include unmanned wireless devices or wireline devices that are used in applications such as status reporting, metering, parcel tracking, telematics, embedded modems for CCTV cameras and consumer electronic devices such as camcorders, cameras, and cable modems, and similar applications.
Wireless MTC devices communicate with one or more servers to exchange information by means of one or more wireless communications networks, such as cellular communications networks or other wide area communications networks. Some MTC devices are required to stay detached from the wireless communications network as long as possible, in order to, for example, conserve battery resources, reduce control signaling with the communications network and reduce the amount of device-specific information (e.g. Mobility Management (MM) context) that must be stored in the communications network. Nevertheless, recent developments in MTC service requirements made by the 3rd Generation Partnership Project (3GPP) working group SA1 have resulted in the requirement that the wireless communications network be able to “trigger” such detached devices. For example, when a MTC server requires information from detached MTC devices, the wireless communications network should be able to trigger or force the MTC devices to attach to the wireless communications network and communicate with the MTC server.
The 3GPP working group SA1 agreed to a change request CR S1-112337 to the 3GPP specification TR 22.368 which introduces the following requirements: A MTC device shall be able to receive trigger indications from the network and shall establish communication with the MTC server when receiving the trigger indication. Possible options may include:                Receiving trigger indication when the MTC device is not attached to the network.        Receiving trigger indication when the MTC device is attached to the network but has no data connection established.        Receiving trigger indication when the MTC device is attached to the network and has a data connection established.        
However, there is currently no solution specified to meet the requirement of an MTC device receiving a trigger indication when it is not attached to the network.
Currently, a wireless communication device that is detached from a communications network is not reachable by the communications network and cannot be triggered by means of downlink signalling to initiate communication with the communications network. The only possibility for a detached wireless communication device to attach to a communications network is by the device initiating communication with the network.
A known solution describes a MTC device that may configure itself to operate in a mobile-originated-only mode in which the MTC device could perform paging monitoring but not cell reselection or location update, or vice versa. The MTC device may receive a trigger from the network, such as a broadcast message or a paging message, to trigger a transition from the mobile-originated-only mode to a mobile-originated-and-terminated mode. This solution however primarily considers the case when the mobile-originated-only mode is an attached mode and only briefly discusses the mobile-originated-only mode as not being an attached mode without providing any details.